President Barack Obama's wife Michelle says she and her husband are "outraged" over the April 14 kidnapping of more than 300 schoolgirls in Chibok, Nigeria.

One day before Americans celebrate Mothers' Day, the first lady stepped in for the president to deliver his weekly broadcast address to the nation, expressing empathy for parents of the 276 girls who are still missing.

"In these girls, Barack and I see our own daughters," she said. "We see their hopes and their dreams, and we can only imagine the anguish their parents are feeling right now."

The first lady also spoke out against the Boko Haram terrorist group that kidnapped the girls. Its leader has said the group intends to sell the girls into slavery.

"This unconscionable act was committed by a terrorist group determined to keep these girls from getting an education — grown men attempting to snuff out the aspirations of young girls," she said.

On Saturday, Saudi Arabia's grand mufti, Sheikh Abdulaziz Al al-Sheikh called the group "misguided" and said the militants had "shown their wrong path."

Separately, the top religious leader in the birthplace of Islam said Boko Haram has been set up to "smear the image of Islam."

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The United States and other countries have sent teams of technical experts to help the Nigerian government in its search effort.

"I want you to know that Barack has directed our government to do everything possible to support the Nigerian government's efforts to find these girls and bring them home," Mrs. Obama said.

Abuja criticized

Nigeria's government has been sharply criticized for its inability to rescue the girls, almost a month after they were taken. But a Nigerian army spokesman, General Chris Olukolade, says it has been a difficult job.

"Some of the information given has turned out, in many occasions, to be misleading and to be exhausting of the search teams," said Olukolade. "Nevertheless, this will not discourage the collaborative efforts that are ongoing."

Rescuing the girls unharmed is the main challenge, according to the director general of the Nigeria Orientation Agency, Mike Omeha.

During a Friday appearance with British High Commissioner Andrew Pocock, Nigerian President Goodluck Jonathan said the kidnappers would fail in their attempts to keep the girls' whereabouts unknown.

"There is nowhere that they can take these girls to," he said, adding that he not be able to sleep with his "two eyes closed" until the girls are free. "They have no hiding place."

On Friday, Amnesty International said Nigerian security forces failed to act on warnings that began coming in more than four hours before Boko Haram attacked the girls' school.

The human rights group blamed the lack of action on an "inability to muster troops," due to poor resources and a possible fear of engaging with the often better-armed militants.

In another development, suspected Islamist militants abducted the wife and two children of a retired police officer during an overnight attack in northern Nigeria.

Local officials and witnesses told VOA on Saturday that the attack took place late Friday in Liman Kara. The town is in the region where the Nigerian government has been battling Boko Haram.

Witnesses say the attackers overpowered local security officials and then set homes on fire and blew up a bridge.

Boko Haram, which wants to impose Islamic Sharia law on Nigeria, has killed more than 1,500 people this year.